Antifungal compositions containing the endophyte fungus alternaria alternata and or its metabolites, as antagonist agents of plasmopara viticola

A process for producing from Alternaria alternata an antagonist extract for Plasmopara viticola comprising:

• a) inoculating culture broth with portions of growing mycelium of Alternaria alternata, incubating possibly with stirring for 12-60 hours, freezing and lyophilizing;
• b) dissolving in water the lyophilized broth obtained from step a), filtering to provide an aqueous filtrate and extracting said the aqueous filtrate with solvent of average polarity, preferably n-butanol, until an organic phase is obtained;
• c) fractionating said organic phase by preparative chromatography on silica layer and eluting with a mixture of n-butanol/acetic acid/water in ponderal ratio 60:15:25 until obtaining three fractions A, B and C;
• and
• d) additionally fractionating the fractions A and B by thin layer chromatography and eluting with a mixture of dichloromethane/methanol in ponderal ratio 9:1 until obtaining the following compounds of formula (1) (Rf s0.48) and (2) (Rf 0.43)